Generation and Regulation of Spontaneous Contractions in the Prostate

2019 ◽  
pp. 195-215
Author(s):  
Basu Chakrabarty ◽  
Sophie Lee ◽  
Betty Exintaris
Keyword(s):  
Spontaneous Contractions

scholarly journals SPONTANEOUS CONTRACTIONS OF THE HUMAN OVARY IN VITRO

Reproduction ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 113-115 ◽  
Author(s):  
Z. PALTI ◽  
M. FREUND
Keyword(s):  
Human Ovary ◽  
Spontaneous Contractions

Vasomotion and Contraction in the Perfused Mesenteric–Portal Vein: Effect of Drugs and Altered Perfusion Pressure

1971 ◽  
Vol 49 (6) ◽  
pp. 615-618 ◽  
Author(s):  
H. James Rhodes ◽  
M. C. Sutter
Keyword(s):  
Portal Vein ◽  
Perfusion Pressure ◽  
Splanchnic Circulation ◽  
Intraluminal Pressure ◽  
Longitudinal Tension ◽  
Portal Veins ◽  
Spontaneous Contractions

Isolated rabbit anterior mesenteric–portal veins (A.M.V.) which possess vasomotion were perfused with Kreb's solution in an apparatus designed so that intraluminal pressure and longitudinal tension could be measured simultaneously. The rate of vasomotion increased as perfusion pressure was increased from 0 to approximately 5 or 6 mm Hg. The amplitude of these spontaneous contractions increased to a maximum at a perfusion pressure of approximately 6 mm Hg and then decreased as perfusion pressure was raised further. Noradrenaline (10−7 g/ml) increased the longitudinal tension, but slightly decreased intraluminal pressure. Isopropylnoradrenaline (10−7 g/ml) had little effect on intraluminal pressure but decreased the amplitude of spontaneous contractions. It is suggested that the effect of perfusion pressure on the frequency and amplitude of vasomotion in the A.M.V. is related to autoregulation and that this perfused preparation may be a useful model for study of the rheology and responses to drugs of the splanchnic circulation.

scholarly journals Contractile activity is required for the expression of neonatal myosin heavy chain in embryonic chick pectoral muscle cultures.

1986 ◽  
Vol 103 (6) ◽  
pp. 2153-2161 ◽  
Author(s):  
L C Cerny ◽  
E Bandman
Keyword(s):  
Monoclonal Antibody ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Contractile Activity ◽  
Pectoral Muscle ◽  
Chicken Muscle ◽  
High K ◽  
Muscle Cultures ◽  
Spontaneous Contractions

The expression of neonatal myosin heavy chain (MHC) was examined in developing embryonic chicken muscle cultures using a monoclonal antibody (2E9) that has been shown to be specific for that isoform (Bandman, E., 1985, Science (Wash. DC), 227: 780-782). After 1 wk in vitro some myotubes could be stained with the antibody, and the number of cells that reacted with 2E9 increased with time in culture. All myotubes always stained with a second monoclonal antibody that reacted with all MHC isoforms (AG19) or with a third monoclonal antibody that reacted with the embryonic but not the neonatal MHC (EB165). Quantitation by ELISA of an extract from 2-wk cultures demonstrated that the neonatal MHC represented between 10 and 15% of the total myosin. The appearance of the neonatal isoform was inhibited by switching young cultures to medium with a higher [K+] which has been shown to block spontaneous contractions of myotubes in culture. Furthermore, if mature cultures that reacted with the neonatal antibody were placed into high [K+] medium, neonatal MHC disappeared from virtually all myotubes within 3 d. The effect of high [K+] medium was reversible. When cultures maintained in high [K+] medium for 2 wk were placed in standard medium, which permitted the resumption of contractile activity, within 24 h cells began to react with the neonatal specific antibody, and by 72 h many myotubes were strongly positive. Since similar results were also obtained by inhibiting spontaneous contractions with tetrodotoxin, we suggest that the development of contractile activity is not only associated with the maturation of myotubes in culture, but may also be the signal that induces the expression of the neonatal MHC.

scholarly journals Chemical composition and spasmolytic activity of Cymbopogon schoenanthus (L.) Spreng. (Poaceae) essential oil from Sudan

2017 ◽  
Vol 69 (3) ◽  
pp. 409-415 ◽  
Author(s):  
Ivan Pavlovic ◽  
Eihab Omar ◽  
Milica Drobac ◽  
Mirjana Radenkovic ◽  
Suzana Brankovic ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Essential Oil ◽  
Essential Oils ◽  
Food Industry ◽  
Experimental Models ◽  
Spasmolytic Activity ◽  
Commercially Important ◽  
Spontaneous Contractions ◽  
Dose Dependent ◽  
Cymbopogon Schoenanthus

The plants of genus Cymbopogon are well known for their use in traditional medicine and for their high content of essential oils that are widely used as flavoring agents, fragrances, cosmetics, and pharmaceuticals. Essential oils isolated from the dried stems and inflorescence of cultivated Cymbopogon schoenanthus (L.) Spreng. (Poaceae) collected from Khartoum state (Sudan) in two periods were studied. The results of chemical analysis of C. schoenanthus revealed that this plant is rich in essential oil which is a valuable source of the commercially important monoterpene, piperitone (47.7-71.5%). Other abundant constituents of the oils were intermedeol (6.1-17.3%), ?-2-carene (4.5-10.0%) and elemol (2.7-9.0%). The essential oil from the inflorescence was tested for spasmolytic activity using three different experimental models: against spontaneous contractions, contractions induced with acetylcholine and contractions induced with potassium chloride. The oil exhibited strong, significant and dose-dependent spasmolytic activity, indicating the possibility for further investigations of this essential oil for its medicinal purposes or application in food industry.

Proctolin induces rhythmic contractions and spikes in Limulus heart muscle

1985 ◽  
Vol 249 (4) ◽  
pp. R490-R495
Author(s):  
W. H. Watson ◽  
T. Hoshi
Keyword(s):  
Heart Muscle ◽  
Input Resistance ◽  
Resting Potential ◽  
Normal Heart ◽  
Cardiac Ganglion ◽  
Long Term Changes ◽  
Rhythmic Contractions ◽  
Spontaneous Contractions

The Limulus heart is neurogenic. If the cardiac ganglion is removed, all spontaneous contractions of the heart are abolished. Application of the pentapeptide proctolin (greater than 1 microM) causes the deganglionated heart muscle to beat with a frequency and amplitude slightly greater than those of a normal heart with an intact cardiac ganglion. At a proctolin concentration of 1 microM, rhythmic beating requires 2–10 min to develop, and up to 1 h of continuous washing is required to reverse the effect. A contracture often precedes the rhythmic contractions. Proctolin-induced rhythmicity occurs in the presence of tetrodotoxin (TTX) and in Na+-free saline. These effects of proctolin are not mediated by residual portions of the cardiac ganglion. Contractions are inhibited by Ca2+-free EGTA saline, CoCl2, MnCl2, and CdCl2. Proctolin causes no significant long-term changes in the myocardial resting potential or apparent input resistance. However, proctolin causes rhythmic 10- to 20-mV spikes that precede each contraction of the myocardium. Production of these spikes appears to be the mechanism by which proctolin causes rhythmic contractions in normally quiescent deganglionated myocardium of Limulus.

Regulation of glycogen accumulation in L6 myotubes cultured under optimized differentiation conditions

1998 ◽  
Vol 275 (6) ◽  
pp. E925-E933 ◽  
Author(s):  
Peter Elsner ◽  
Bjørn Quistorff ◽  
Thomas S. Hermann ◽  
John Dich ◽  
Niels Grunnet
Keyword(s):  
Retinoic Acid ◽  
Glycogen Synthase ◽  
Accumulation Rate ◽  
Decisive Role ◽  
Glycogen Metabolism ◽  
Total Activity ◽  
Glycogen Accumulation ◽  
L6 Myotubes ◽  
Igf I ◽  
Spontaneous Contractions

The differentiation of the L6 myogenic cell line was enhanced by the addition of dexamethasone, retinoic acid, insulin-like growth factor I (IGF-I), and creatine. Spontaneous contractions appeared from day 10 or 11 and persisted to day 14 or 15. Glucose transport was increased by insulin (100 nM) and IGF-I (5 nM) by ∼60%. The highest level of glycogen was measured in myotubes differentiated under the influence of a combination of 5 nM dexamethasone, 100 nM retinoic acid, 5 nM IGF-I, and 10 mM creatine with glucose as substrate. The glycogen accumulation rate was constant from 0 to 2 h of incubation and decreased gradually to zero at 4 h. From 0 to 0.5 h of the glycogen accumulation, the glycogen synthase a(GS a) activity was 30–35% of the total activity, with a subsequent gradual decline to 2.5% after 6 h. The glycogen phosphorylase a(GPh a) activity was constant at ∼80% from 0 to 0.5 h, increasing to ∼100% after 6 h. The activity ratio of GS a to GPh a decreased about sixfold without significant change in the rate of glycogen accumulation. This indicates that factors other than phosphorylation/dephosphorylation play a decisive role in the regulation of glycogen metabolism in L6 myotubes. Intracellular glucose (glucosei) and glucose 6-phosphate (G-6- P) may be such factors. The observed values of these parameters may in fact explain an activation of GS a(G-6- P) and an inhibition of GPh a(glucosei).

Seminal vesicle response to androgen with adrenaline, noradrenaline and acetylcholine

1960 ◽  
Vol 198 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Jerome A. Grunt ◽  
James T. Higgins
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Seminal Vesicle ◽  
Testosterone Propionate ◽  
Water Soluble ◽  
Muscle System ◽  
Motor End Plate ◽  
Organ Response ◽  
Spontaneous Contractions

In a study of the end-organ response to androgen, use has been made of the seminal vesicle of the rat. Observations were made of the in vitro spontaneous contractions and responses to autonomic stimulating drugs. Vesicles of castrated rats contract spontaneously in vitro. Testosterone propionate given to the rat before sacrifice inhibits contractions, as does injection of water-soluble androgen into the in vitro chamber. Vesicles of castrates have lower thresholds to adrenaline and possibly to acetylcholine, but not to noradrenaline. The thresholds to acetylcholine but not to noradrenaline are elevated after injection of water-soluble androgen into the in vitro chamber. Several interpretations are discussed. Androgen and the autonomic nervous system probably interact at or near the cell membrane of the vesicle musculature. The three drugs tested most likely act at different loci along the nerve—motor end plate—muscle system, and noradrenaline is probably not a primary mediating agent of spontaneous contractions of the vesicle of the castrated rat.

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